From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755422Ab1BWJj5 (ORCPT ); Wed, 23 Feb 2011 04:39:57 -0500 Received: from mail-fx0-f46.google.com ([209.85.161.46]:60749 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755049Ab1BWJjz (ORCPT ); Wed, 23 Feb 2011 04:39:55 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=E26jRtBKhbPDWOKb53d09YoSVtxpJvercoW7B3iTt+j/ecRK9A2N/8JLICgQL+0YnD B1SdrGsU4wyhPXAfirn5lw6WSCF1g0ZnVpaVTVp6r6rZH1rjwBYIb/px6YxbsIO29fx9 MIGm0Xpgypdc/rTgwZnHIHCjEEAbR8T+Rr6+g= Date: Wed, 23 Feb 2011 10:38:54 +0100 From: Tejun Heo To: Dmitry Torokhov Cc: "pantherchen@versanet.de" , "linux-kernel@vger.kernel.org" Subject: Re: Boot time regression in 2.6.38 after initial wq merge Message-ID: <20110223093854.GB26065@htj.dyndns.org> References: <20110222085223.GC11681@core.coreip.homeip.net> <20110222090255.GR31267@htj.dyndns.org> <4D63D062.3040404@versanet.de> <20110222172254.GA13114@core.coreip.homeip.net> <20110222175955.GA27991@core.coreip.homeip.net> <4D640F67.3040109@versanet.de> <20110222195257.GA13256@core.coreip.homeip.net> <4D641936.90404@versanet.de> <20110223052042.GA19269@core.coreip.homeip.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110223052042.GA19269@core.coreip.homeip.net> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Tue, Feb 22, 2011 at 09:20:42PM -0800, Dmitry Torokhov wrote: > On Tue, Feb 22, 2011 at 09:14:46PM +0100, pantherchen@versanet.de wrote: > > On 02/22/2011 08:52 PM, Dmitry Torokhov wrote: > > >Ewww... tty/ldisc... > > > > > >Does it help if you change drivers/input/serio/serio.c::serio_queue_event() > > >from calling > > > > > > schedule_work(&serio_event_work); > > > > > >to call > > > > > > queue_work(system_long_wq,&serio_event_work); > > > > > >? > > > > Yes, that works: http://img.xrmb2.net/images/499337.png > > > > Great! > > OK, so below is properly formatted patch. I am going to send it upstream > unless somebody objects. Ah, okay, thanks a lot for tracking this down, Dmitry. Didn't expect flush_scheduled_work() to bite back this way. :-) > Input: serio/gameport - use 'long' system workqueue > > From: Dmitry Torokhov > > Commit 8ee294cd9def0004887da7f44b80563493b0a097 converted serio > subsystem event handling from using a dedicated thread to using > common workqueue. Unfortunately, this regressed our boot times, > due to the fact that serio jobs take long time to execute. While > the new concurrency managed workqueue code manages long-playing > works just fine and schedules additional workers as needed, such > works wreck havoc among remaining users of flush_scheduled_work(). > > To solve this problem let's move serio/gameport works from system_wq > to system_long_wq which nobody tries to flush. > > Reported-and-tested-by: Hernando Torque > Signed-off-by: Dmitry Torokhov Acked-by: Tejun Heo Most flush_scheduled_work() users are already gone and once all of them are gone, system_long_wq can be removed without causing any difference. Thank you. -- tejun